I had to break out the concrete around the tub drain to get the elbow low enough to provide a slope on the tub drain. I had to reveal enough pipe to glue on the elbow under the floor surface.
I used the street elbow to attach a 2″ to 1 1/2″ adapter for the tub drain piping.
I tried just chipping out the concrete with a 5 pound hammer and cold chisels but the work was too slow and I was afraid I would crack the drain pipe.
So I brought out the big guns. I have a Harbor Freight electric demolition hammer and that did the trick.
My hammer is green and a bit different from the model they sell now. I bought it way back in 2012 when I was curious what was under the original concrete floor.
It was short work to chip out enough concrete to reveal the 3/4″ or so that is needed to glue on the elbow close to the floor.